The Indiana Utility Regulatory Commission (IURC) adopted rules for net metering in September 2004, requiring the state's investor-owned utilities (IOUs) to offer net metering to all electric customers. The rules, which apply to renewable energy resource projects [defined by IC 8-1-37-4(a)(1) - (8)] with a maximum capacity of 1 megawatt (MW), include the following provisions:

A utility may limit the aggregate amount of net-metering (nameplate) capacity to 1% of its most recent summer peak load.

At least 40% of a utility's bet metering capacity must be residential customers.

An interconnection agreement between the utility and the customer must be executed before the facility may be interconnected.

Utilities may not charge customers any fees for additional metering for single-phase configurations installed by the utility, for customers' requests to net meter, or for an initial net-metering facility inspection.

Net metering customers must maintain homeowners, commercial, or other insurance providing coverage of at least $100,000 against loss arising out of the use of a net metered facility. Utilities may not require additional liability insurance in excess of this limit.

Net excess generation (NEG) is credited to the customer's next monthly bill. The rules do not address the expiration of NEG for continuous customers. (If a customer elects to cease net metering, any unused credit will revert to the utility.)

Any disputes between customers and utilities will be settled according to the IURC's consumer-complaint rules.

Before the IURC issued mandatory net-metering rules in September 2004, three of the state's IOUs -- Indianapolis Power and Light Company (IPL), Southern Indiana Gas and Electric Company (SIGECO), and PSI Energy -- voluntarily offered net metering to customers with renewable-energy systems. IOUs may choose to offer larger net metering capacity limits. For example, as of spring 2010 Indianapolis Power and Light Company voluntarily raised its net metering program capacity limits to 50 kW and made net metering available to all customer classes, as part of its demand side management programs approved by the IURC (Cause number 43623).
In May 2011, the IURC approved final rules (effective July 13, 2011) increasing the maximum net metering capacity from 10 kW to 1 MW, and increasing the aggregate capacity limit from .1% to 1% of the most recent summer peak load. All electric customers are now eligible to net meter. In addition, the rulemaking defined "name plate capacity" for inverter-based net metering facilities to be "the aggregate output rating of all inverters in the facility, measured in kW." Government entities are now exempt from the indemnification provision. Lastly, the rulemaking allows all "renewable energy resources" as defined by IC 8-1-37-4(a)(1) through IC 8-1-37-4(a)(8)*.

In March 2012, the IURC issued a net metering report summarizing the net metering customers through 2011.

*In the original version of the final rules, there was a typographical error related to eligible resources. RM#09-10 LSA#10-662(ac) corrects the error, clarifying the list of eligible technologies as IC 8-1-37-4(a)(1) through IC 8-1-37-4(a)(8).